66 THE THEORY OF IONS 



When ammonia is approached by a hydrocarbon 

 radical we get an amido-compound : 



NH 3 + CH 3 - H + CH 5 N or methylamine. 



If another H is removed from the ammonia we shall 

 have NH 2 , which is an ammonia-rest, the amido- 

 group, a monovalent ion. Primary, secondary, 

 tertiary, and quaternary compounds of this group 

 are called Amines, or combinations of ammonia with 

 hydrocarbons. 



Mono-amines, primary ammonia bases or amido- 

 bases, contain one molecule of NH 3 in which one II 

 is replaced by an alcohol-radical, e.g. methylamine, 

 ethylamine, propylamine, and benzylamine. In the 

 secondary bases two H atoms are replaced by two 

 hydrocarbon radicals ; in tertiary bases all three 

 H atoms are replaced by hydrocarbon radicals ; and 

 in quaternary bases the triad nitrogen of the 

 ammonia turns into a pentad. 



Di-amines contain two molecules of ammonia, in 

 which the hydrogen atoms may be similarly dis- 

 placed by hydrocarbons. Poly-amines contain three 

 or more ammonia or amido-groups, in which the H 

 atoms of the group have been replaced by a similar 

 number of hydrocarbon radicals. 



Nitrogen becomes a pentad when joined to OH 

 or other electro-negative ions if there is an electro- 

 positive ion at hand to take up the fifth valency. 

 If there is not, the ammonia gives up one of its H 

 atoms to a hydroxyl ion to form water, and the 

 result is hydroxyl-amine, NH 3 or NH 2 -OH. 



NH 3 0+H 2 0. 



